Certain substituted polymercaptan derivatives of pyridine and benzene



United States Patent US. Cl. 260-2943 2 Claims ABSTRACT OF THEDISCLOSURE Polymercaptans of the general formula:

wherein A is nitrogen or CH, R is an alkylene radical of 1 to 6 carbonatoms, n is an integer of 3 to 4, and the ring carbon atoms not attachedto the -RSH groups are attached to a hydrogen, halogen or alkyl radicalof up to 4 carbons atoms are useful for curing polyepoxides.

This application is a division of our application Ser. No. 284,322,filed May 31, 1963, now U.S. Patent No. 3,310,- 527, issued on Mar. 21,1967.

This invention relates to a process for curing polyepoxides. Moreparticularly, the invention relates to a new process for curingpolyepoxides using a special type of cyclic polymercaptan curing agent,and to the useful products obtained therefrom.

Specifically, the invention provides a new process for curing andresinifying polyepoxides at a rapid rate at low reaction temperatureswhich comprises mixing and reacting the polyepoxide with a compundhaving at least three mercapto-substituted side chains attached to oneor more aromatic rings or rings which have aromatic characteristics, andpreferably in addition an accelerating material such as, for example, atertiary amine. The invention further provides cured products obtainedby the above-described process.

Polyepoxides, such as, for example, those obtained by reactingepichlorohydrin with polyhydric phenols in the presence of caustic, arepromising materials for use in many industrial applications as they canbe reacted with curing agents to form insoluble infusible productshaving good chemical resistance. The conventional polyepoxidecuringagent systems, however, have certain drawbacks that have limited theiruse for certain applications. For example, the known systems takeconsiderable time to cure at low temperatures. With the best aliphatictype amine curing agents the systems take several hours to set to a hardproduct. Furthermore, because of the extended cure time, the epoxycoatings tend to react with atmospheric materials such as carbon dioxideand water, giving products having poor properties, such as blushing andthe like. Because of this, it has been diificult to use the polyepoxidesystems for applications, such as highway coatings, maintenance surfacecoatings and the like, where the coating must dry in a very short time,or for quality surface coatings which must cure in a short period togive a superior film.

It has been found that certain types of polymercaptans 3,448,112Patented June 3, 1969 can be used to cure the polyepoxides at a rapidrate at the low temperatures. The use of these materials, however, hasbeen limited because they have a strong odor, in some cases are toxic,and in most cases are very thick liquids or solids which are difficultto mix with the polyepoxides. Furthermore, the properties of the curedproducts are not as good as desired for certain applications.

It is an object of the invention, therefore, to provide a new processfor curing polyepoxides. It is a further object to provide a new processfor curing polyepoxides at a fast rate at low temperatures. It is afurther object to provide a process for curing polyepoxides to a hardproduct in a matter of minutes. It is a further object to provide aprocess for curing polyepoxides at a fast rate to give superior productsfree of blushing and the like. It is a further objective to provide arapid cure which avoids extensive reaction with carbon dioxide andwater. It is a further object to provide a process for curingpolyepoxides at a fast rate to form products having good strength andresistance to water, solvents and alkali. It is a further object toprovide new low temperature curing agents for polyepoxides which havelittle or no odor. It is a further object to provide new curing agentsfor polyepoxides which are substantially non-toxic. -It is a furtherobject to provide a new class of polymercaptans that can be used to curepolyepoxides at low temperatures. These and other objects of theinvention will be apparent from the following detailed descriptionthereof.

It has now been discovered that these and other objects may beaccomplished by the use as curing agents for the polyepoxides of certainpolymercaptans which have at least three mercapto-substituted sidechains attached to one or more aromatic rings or rings which havearomatic characteristics, such as, for example, a tri(mercapto methyl)substituted diphenyl oxide. It has been found that these specialpolymercaptans when combined with the polyepoxides, particularly incombination with an accelerator such as, for example, a tertiary amine,cure the polyepoxide in a matter of minutes to form a hard coating.Furthermore, the cured product has excellent hardness and strength andgood resistance to water, solvents and alkali. Of particular importanceis the fact that these special mercaptans have ilttle, if any, odor, aresubstantially non-toxic and are generally liquids which can be easilymixed into the polyepoxide compositions without the use of solvents ordiluents.

The new curing agents to be used in the process of the inventioncomprise the cyclic compounds having at least three mercapto-substitutedside chains attached to one or more aromatic rings or rings havingaromatic characteristics. By aromatic type is meant those fullyconjugated planar cyclic systems possessing (4n+2)m' electrons andhaving substantial resonance energy. See Perspectives in OrganicChemistry, by Todd, pages 33 to 40. The compounds are preferablymononuclear but may contain two or more ring structures which may befused or coupled together through a single bond or through anotherradical or radicals. The rings may be joined through a variety ofcoupling agents, such as alkylene groups, sulfur, oxygen, nitrogen,phosphorous atoms and the like. The side chains may contain other groupsin addition to the mercaptan group, such as, OH, ether, esters, etc. Themercapto groups are preferably not more than 6 carbon atoms removed fromthe ring.

1,2,4-tri(mercaptomethyl) benzene, 1,2,3-tri(-mercaptomethyl) benzene,l,3,5-tri(mercaptomethyl) benzene,

1,3,5 -tri (mercaptomethyl) -4-methyl benzene,

l ,2,4-tri mercaptoethyl -5-isobutyl benzene, 1,2,3-tri (mercaptomethyl)-4,5-diethyl benzene,

1,3,5-tri(mercaptomethyl)-2,6-dimethyl benzene,1,3,5-tri(mercaptomethyl)-4-hydroxy benzene,l,2,3-tri(mercaptomethyl)-4,6-dihydroxy benzene, 1,2,4-tri(mercaptomethyl) -3-methoxy benzene, 1,2,4-tri(mercaptoethyl)-4-aminoethyl benzene, 1,3,5-tri(mercaptobutyl) -4-butoxy benzene,1,2,4,5-tetra(mercaptomethyl)-3,6-dimethyl benzene,l,2,4,5-tetra(mercaptoethyl)-3,6-dimethoxy benzene, 1,2,4-tri(mercaptomethyl) -3 (N,N- dimethyl amino benzene, 1,3 ,5 -tri(mercaptobutyl) -4- (N,N-dibutylamino) benzene,1,2,4,5-tetra(mercaptomethyl -3,6-dihydroxy benzene,3,4,5-tri(mercaptomethy1) furan, 2,3,5-tri(mercaptoethyl) furan,2-butyl-3,4,5-tri(mercaptomethyl) furan, 3,4,5-tri(mercaptomethyl)thiophene, 2,3,5-tri(mercaptomethyl) thiophene,2-isobutyl-3,4,5-tri(mercaptoethyl) thiophene, 3,4,5-tri(mercaptobutyl)pyrrole, 2,3,5-tri(rnercaptomethyl) pyrrole 2,4,6-tri(mercaptomethyl)pyridine, 2,3,5-tri(mercaptomethyl) pyridine, 2,4,6-tri(mercaptomethyl)-5-butyl pyridine, 2,4,6-tri(mercaptomethyl) -5-viny1 pyridine,2,3,5-tri(mercaptobutyl)-4-allyl pyridine, 2,3,5-tri(mercaptomethy1)thionaphthene, 2,3,5-tri(mercaptornethyl) quinoline,3,4,6-tri(mercaptomethyl) isoquinoline.

Other examples of these compounds include, among 0 others, thepoly(mercaptoalky1) substituted benzenes, the poly(mercaptoalkyl)substituted naphthalenes, the poly- (mercaptoalkyl) substitutedbisphenyls, the poly(mercaptoalkyl) substituted bis(phenyl) alkanes,poly(tmercaptomethyl) bis(hydroxyphenyl) alkanes, thepoly(mercaptoalkyl) substituted bis(hydroxyphenyl) sulfones,poly(mercaptomethyl) substituted bis(phenyl) sulfone, thepolymercaptoalkyl) substituted bis(hydroxyphenyl) sulfides, thepoly(mercaptoalkyl) substituted bis(hydroxyphenyl) oxides,poly(mercaptoalky1) substituted bis(phenyl) oxides, poly(mercaptoalkyl)substituted bis(chlorophenyl) alkanes and the like.

Specific examples include, among others:

4-mercaptomethylphenyl-4',5'-dimercaptomethylphenylmethane,2,2-bis(4,S-dimercaptomethylphenyl) propane,2,2-bis(4,fi-dimercaptobutylphenyl) butane,4-mercaptomethylphenyl-3',4-dimercaptomethylphenyl oxide,4-mercaptomethylphenyl-3',4'-dimercaptomethylphenyl sulfone,2,2-bis(4,S-dimercaptoethylphenyl) sulfide, the3,4-dimercaptomethylphenyl ester of carbonic acid, the3,4-dimercaptoethylphenyl ester of maleic acid,1,3,5-tri(mercaptomethyl) 2,4,6-trimethylbenzene,2,2-bis(3-butyl-4,S-dimercaptoethylphenyl) hexane,l,3,5-tri(4-imercapto-2-thiabutyl) benzene,1,3,5-tri(4-mercapto-2-oxabutyl) benzene,2,3-bis(4,5-dimercaptobutyl-3-chlorophenyl) butane,4-mercaptobutylphenyl-3',4'-dimercaptomethylphenyl oxide,3-mercaptobutylphenyl-Z,4'-dimercaptobutylphenyl oxide,

and compounds of the formula CHzSH and C HzSH Also included in the aboveare the polymeric polymer- 4 captans as obtained by joining two or moreof the above compounds together as 0 H2811 C HzSH CHzSH or by couplingreactions with dialdehydes and the like.

Preferred members of the above group comprise the polymercaptans of thegeneral formulae and (ESRhQ-X-G-QRSHM wherein R is an organic radicaland preferably a hydrocarbon or thia or oxo-substituted hydrocarbonradical containing 1 to 10 carbon atoms, n is an integer of at least 3,and preferably 3 to 5, X is nothing or a coupling group as an alkyleneradical, S, O, or hydrocarbon radical containing S and 0, one m is atleast 2, and the other m is an integer of 1 or more, with the total ofthe 2 ms being preferably from 3 to 5.

Of special interest are the poly(mercaptoalkyl) benzenes,poly(mercaptoalkyl) biphenyls, the poly(mercaptoalkyl) bisphenylalkanes, the poly(mercaptoalkyl) bisphenyl sulfides, thepoly(mercaptoalkyl) bisphenyl oxides, and the poly(mercaptoalkyl)bisphenyl sulfones, wherein there are at least three of the saidmercaptoalkyl groups and each alkyl group contains from 1 to 5 carbonatoms.

Also of special interest are those of the formula:

wherein A is a member of the group consisting of nitrogen or CH, R is abivalent radical, such as an aliphatic radical, containing 1 to 6 carbonatoms, 11 is an integer of 3 to 5, and the ring carbon atoms notattached to the -RSH groups are attached to a member of the groupconsisting of hydrogen, halogen, and alkyl radicals, and those ofrelated formula wherein A is a member of the group consisting of O, Nand S and R is as noted above, n is an integer of 3 to 4 and the ringcarbon atoms not attached to the --RSH groups are attached to a memberof the group consisting of hydrogen, halogen, and alkyl radicals.

The polymercaptans of the present invention can be prepared by a varietyof different methods. They may be prepared, for example, by reacting thecorresponding chloride compound with an alkali metal hydrosulfide, suchas NaSH. The corresponding chlorides may be prepared by any of theconventional techniques. The chloromethyl derivatives, for example, maybe obtained by the wellknown method of reacting the aromatic compound oraromatic acting compound with formaldehyde and HCl.

The reaction of the chlorides with the sodium bisulfide is illustratedby the following equation showing the preparation of4-mercaptomethylphenyl-3,4-dimercaptomethylphenyl oxide from4-chloromethylpheny1-3',4'- di (chloromethyl phenyl oxide momQoQ-ommnsom-Q-oQ-omsn 3NaC1 bisnsn The sodium hydrosulfide used in the reactionis preferably formed in situ by the reaction of NaOH with hydrogensulfide. The sodium hydrosulfide is preferably employed in excess ofthat needed to convert the halogen atoms, and is preferably used inamounts varying from about 2 to 5 times the amount needed forconversion. The reaction with the sodium hydrosulfide is preferablyaccomplished in the presence of a solvent, such as ethanol, methanol,tetrahydrofuran, water or mixtures thereof. The temperature employed inthe reaction will preferably vary from about 40 C. to about 150 C. witha preferred range varying from about 40 C. to 80 C. In recovering thedesired product, the hydrogen sulfide pressure is released, the reactionmixture neutralized with acetic acid and the mixture stripped of solventand distilled or extracted to obtain the desired polymercaptan.

The above desired new polymercaptans of the present invention are fluidto viscous liquids or solids. They have active mercapto groups and atleast three per molecule. They are generally free of odor andsubstantially nontoxic. They are soluble in conventional solvents, suchas benzene, hydrocarbons, ethers, esters and the like. They are alsocompatible with conventional resins, tars, oils, polymers and the like,such as asphalts, coal tars, rosin, phenol-formaldehyde resins, vinylpolymers, and particularly epoxy resins.

As noted above, they are particularly useful and valuable as curingagents for the polyepoxides.

The polyepoxides to be used in the process of the invention comprisethose materials possessing more than one vicinal epoxy group, i.e., morethan one group. These compounds may be saturated or unsaturated,aliphatic, cycloaliphatic, aromatic or heterocyclic and may besubstituted with substituents, such as chlorine, hydroxyl groups, etherradicals and the like. They may be monomeric or polymeric.

For clarity, many of the polyepoxides and particularly those of thepolymeric type are described in terms of epoxy equivalent values. Themeaning of this expression is described in U.S. 2,633,458. Thepolyepoxides used in the present process are those having an epoxyequivalency greater than 1.0.

Various examples of polyepoxides that may be used in the process of theinvention are'given in U.S. 2,633,458 and it is to be understood that somuch of the disclosure of that patent relative to examples ofpolyepoxides is incorporated by reference into this specification.

Other examples include the epoxidized esters of the polyethylenicallyunsaturated monocarboxylic acids, such as epoxidized linseed, soybean,perilla, oiticica, tung, walnut, and dehydrated castor oil, methyllinoleate, butyl linoleate, ethyl 9,12-octadecadienoate, butyl9,12,15-octadecatrienoate, butyl eleostearate, monoglycerides of tungoil fatty acids, monoglycerides of soybean oil, sunflower, rapeseed,hempseed, sardine, cottonseed oil and the like.

Another group of the epoxy-containing materials used in the process ofthe invention include the epoxidized esters of unsaturated monohydricalcohols and polycarboxylic acids, such as, for example,di(2,3-epoxybutyl) adipate, di(2,3-epoxybutyl) oxalate,di(2,3-epoxyhexyl) succinate, 'di(3,4-epoxybutyl) maleate,di(2,3-epoxyoctyl) pimelate, di(2,3-epoxybutyl) phthalate, di(2,3-

epoxyoctyl) tetrahydrophthalate, di(4,5-epoxydodecyl) maleate,di(2,3-epoxybutyl) tetraphthalate, di(2,3-epoxypentyl) thiodipropionate,di(5,6-epoxytetradecyl) diphenyldicarboxylate, di(3,4-epoxyheptyl)sulfonyldibutyrate, tri(2,3-epoxybutyl) 1,2,4-butanetricarboxylate, di-(5,6-epoxypentadecyl) tartarate, di(4,5-epoxytetradecyl) maleate,di(2,3-epoxybutyl)azelate, di(3,4-epoxybutyl) citrate,di(5,6-epoxyoctyl) cyclohexane-1,2-dicarboxylate, di(4,5-epoxyoctadecyl)malonate.

Another group of the epoxy-containing materials includes thoseepoxidized esters of unsaturated alcohols and unsaturated carboxylicacids, such as 2,3-epoxybutyl 3,4-epoxypentanoate, 3,4-epoxyhexyl3,4-epoxyhexyl 3,4- epoxypentanoate, 3,4-epoxycyclohexyl3,4-epoxycyclohexanoate, 3,4-epoxycyclohexyl 4,5-epoxyoctanoate, 2,3-epoxycyclohexylmethyl epoxycyclohexane carboxylate.

Still another group of the epoxy-containing materials includedepoxidized derivatives of polyethylenically unsaturated polycarboxylicacids such as, for example, dimethyl 8,9,12,13-diepoxyeicosanedioate,dibutyl 7,8,11,- 12 diepoxyoctadecanedioate, dioctyl 10,11 diethyl-8,9,12,13 diepoxyeicosanedioate, dihexyl6,7,10,1l-diepoxyhexadecanedioate, didecyl 9 epoxyethyl 10,11-epoxyoctadecanedioate, dibutyl3-butyl-3,4,5,6-diepoxycyclohexane-l,2-dicarboxylate, dicyclohexyl3,4,5,6-diepoxycyclohexane-1,2-dicarboxylate, dibenzyl1,2,4,5-diepoxycyclohexane-1,2-dicarboxylate and diethyl 5,6,10,-ll-diepoxyoctadecyl succinate.

Still another group comprises the epoxidized polyesters obtained byreacting an unsaturated polyhydric alcohol and/or unsaturatedpolycarboxylic acid or anhydride groups, such as, for example, thepolyester obtained by reacting 8,9,12,13-eic0sanedienedioic acid withethylene glycol, the polyester obtained by reacting diethylene glycolwith 2-cyclohexene-1,4-dicarboxylic acid and the like, and mixturethereof.

Still another group comprises the epoxidized polyethylenicallyunsaturated hydrocarbons, such as epoxidized 2,2bis(2-cyclohexenyl)propane, epoxidized vinyl cyclohexene and epoxidized dimer ofcyclopentadiene.

Another group comprises the epoxidized polymers and copolymers ofdiolefins, such as butadiene. Examples of this include, among others,butadiene-acrylonitrile copolymers (Hycar rubbers), butadiene-styrenecopolymers and the like.

Another group comprises the glycidyl containing nitrogen compounds, suchas diglycidyl aniline and diand triglycidylamine.

The polyepoxides that are particularly preferred for use in thecompositions of the invention are the glycidyl ethers and particularlythe glycidyl ethers of polyhydric phenols and polyhydric alcohols. Theglycidyl ethers of polyhydric phenols are obtained by reactingepichlorohydrin with the desired polyhydric phenols in the presence ofalkali. Polyether A and Polyether B described in the above-noted U.S.2,633,458 are good examples of polyepoxides of this type. Other examplesinclude the polyglycidyl ether of1,1,2,2-tetrakis(4-hydroxyphenyl)ethane (epoxy value of 0.45 eq./ 100g.) and melting point C., polyglycidyl ether of1,1,5,5-tetrakis(hydroxyphenyl) pentane (epoxy value of 0.514 eq./ g.)and the like and mixtures thereof.

The amount of new polymercaptans to be employed in the cure of thepolyepoxide may vary within certain limits. In general, the polyepoxidesare combined with at least .8 equivalent of the polymercaptan. As usedherein equivalent amount refers to that amount needed to furnish one -SHgroup per epoxy group to be reacted. Preferably the polymercaptans andpolyepoxides are combined in chemical equivalent ratios varying from.8:l.5 to 1.5 :.8.

It is preferred in some cases to employ activators for the cure.Examples of these include, among others, phenols, sulfides, organicphosphines, organic arsines, organic antimony compounds, amines, aminesalts or quaternary ammonium salts, etc. Preferred activators are thephenols,'phosphines, arsines, amines, and sulfides, such as, forexample, benzyldimethylamine, dicyandiamide,p,p'-bis(dimethylaminophenyl) methane, pyridine, dimethyl aniline,dimethylethanolamine, methyldiethanolamine, morpholine,dimethylaminopropylamine, dibutylaminopropylamine, stearyldimethylamine,tri-n-butylamine, tri-n-hexylamine, ethyl di-n-propylamine, dibutylsulfide, dioctyl sulfide, dicyclohexyl sulfide and the like, andmixtures thereof. The salts may be exemplified by the inorganic andorganic acid salts of the amines, such as, for example, thehydrochloride, sulfate and acetate of each of the above-describedtertiary amines. The quaternary ammonium salts may be exemplified by thefollowing: benzyltrimethylammonium chloride, phenyltributylammoniumchloride, cyclohexyltributylammonium sulfate, benzyltrimethylammoniumsulfate, benzyltrimethylammonium borate, diphenyldioctylammoniumchloride, and the like, and mixtures thereof.

Preferred activators to be used are the sulfides, phosphines andtertiary amines, and more preferably the monoand diamines wherein theamine hydrogens have been replaced by aliphatic, cycloaliphatic oraromatic hydrocarbon radicals containing not more than 15 carbon atoms,such as, for example, the trialkyl amines, triaryl amines,triarylalkylamines, alkyl arylalkylamines, tricycloalkylamines, alkyldicycloalkylamines, diaminoalkanes, and di(aminoaryl) alkanes. Preferredamine salts are the hydrochloride, sulfate and acetate of theabovedescribed preferred amines. The preferred quaternary salts arethose of the formula 2 1 X R R wherein Y is nitrogen, R is an alkyl,aryl or arylalkyl radical, preferably containing no more than 12 carbonatoms and X is chlorine.

The activators noted above are generally employed in amounts varyingfrom 0.1 part to 4 parts per 100 parts of polyepoxide, and preferablyfrom 1 part to 3 parts per 100 parts of polyepoxide.

In curing the polyepoxides, it is usually desirable to have thepolyepoxide in a mobile condition when the polymercaptan is added inorder to facilitate mixing. The polyepoxides, such as the glycidylpolyether of polyhydric phenols, are generally very viscous to solidmaterials at ordinary temperature. With those that are liquid, but tooviscous for ready mixing, they are either heated to reduce theviscosity, or have a liquid solvent added thereto in order to providefluidity. Normally solid members are likewise either melted or mixedwith a liquid solvent. Various solvents are suitable for achievingfluidity of the polyepoxide. These may be volatile solvents which escapefrom the polyepoxide compositions containing the adduct by evaporationbefore or during the curing such as, esters such as ethyl acetate, butylacetate, Cellosolve acetate (ethylene glycol monoacetate), methylCellosolve acetate (acetate ethylene glycol monomethyl ether), etc.,ether alcohols such as methyl, ethyl or butyl ether of ethylene glycolor diethylene glycol; chlorinated hydrocarbons such as trichloropropane,chloroform, etc. To save expense, these active solvents may be used inadmixture with aromatic hydrocarbons such as benzene, toluene, xylene,etc., and/or alcohols such as ethyl, isopropyl or n-butyl alcohol.Solvents which remain in the cured compositions may also be used, suchas diethyl phthalate, dibutyl phthalate and the like, as well ascyano-substituted hydrocarbons, such as acetonitrile, propionitrile,adiponitrile, benzonitrile, and the like. It is also convenient toemploy a polyepoxide, such as one of the glycidyl polyethers of thedihydric phenol, in admixture with a normally liquid glycidyl polyetherof a polyhydric alcohol. In fact, two or more of any of the polyepoxidesmay be used together as mixtures. In such a case, the amount oftheadduct added and commingled 8 is based on the average epoxide equivalentweight of the polyepoxide mixture.

Various other'ingredients may be mixed with the polyepoxide subjected tocure with the novel adducts including pigments, fillers, dyes,plasticizers, resins, and the like.

The polyepoxides may be cured with the new polymercaptans by merelymixing the two components together, preferably in the presence of theabove-noted activators. The cure time may vary from a few minutes to afew hours, depending on the type and quantity of reactants and presenceof catalyst. In general, in the presence of activators, the cure takesplace readily at room temperature. Fast reaction may be obtained, ofcourse, by applying heat. Preferred temperatures range from about 20 C.to 200 C. With small castings, it is preferred to cure at roomtemperature and then post cure for a few minutes.

One important application of the use of the new polymercaptans as curingagents for polyepoxides is .in the preparation of laminates or resinousparticles reinforced with fibrous textiles. Although it is generallypreferred to utilize glass cloth for this purpose any of the othersuitable fibrous materials in sheet form may be employed such as glassmatting, paper, asbestos paper, mica flakes, cotton bats, duck muslin,canvas and the like. It is useful to prepare the laminates from wovenglass cloth that has been given prior treatment with Well-knownfinishing or sizing agents, therefore, such as chrome methacrylate.

or vinyl trichlorosilane.

In preparing the laminate, the sheets of fibrous materials arepreferably first impregnated with the mixture of the polyepoxide,polymercaptan and activator. This conveniently accomplished bydissolving the polymercaptan in a solvent and mixing the solution withthe polyepoxide so as to obtain a fluid mixture. The sheets of fibrousmaterial are impregnated with the mixture by spreading it thereon or bydipping or otherwise immersing them in the impregnant. The solvent isconveniently removed by evaporation and the mixture is cured by theapplication of heat. A plurality of the impregnated sheets can besuperimposed and the assembly cured in a heated press under a pressureof about 25 to 500 or more pounds per square inch. The resultinglaminate is extremely strong and resistant against the action of organicand corrosive solvents.

The new compositions of the invention are particularly outstanding asadhesives. In this application they can be used as a paste or solutiondepending on the method of preparation asdescribed above. Othermaterials may also be included in the composition, such as pigments,plasticizers, stabilizers and reinforcing fillers, such as aluminumpowder, asbestos, powdered mica, zinc dust, bentonite, ground glassfibers, Monetta clay and the like. These fillers are preferably used inamounts varying from about 10 parts to 200 parts per parts of thepolyepoxide and polymercaptan compound. Other materials that may beincluded include other types of resins, such as phenol-aldehyde resins,urea-aldehyde resins, furfural resins, polyacetal resins, carbonateresins, polyamide resins, and the like.

The compositions may be used in the bonding of a great variety ofdifferent materials, such as metal-to-metal to other materials, such asplastic, wood-to-wood, glass-toglass, glass-to-metal, and the like. Theyare of particular value, however, in the bonding of metals such asaluminum-to-aluminum and steel-to-steel. When applied as an adhesive,the composition may simply be spread on the desired surface to formfilms of various thicknesses, e.g., 0.5 mil to 30 mils, and then theother surface superimposed and heat applied. Curing pressures can belight contact pressures up to about 500 psi.

When the compositions are used as adhesives for metalto-metal bonding,it has sometimes been found advantageous to impregnate cotton, rayon,synthetic fiber or glass cloth textiles with the compositions, and thenuse the impregnated textiles as a bonding tape for joining the metals.

Such tapes provide convenient means for handling and using thecompositions in adhesive applications. The tape is inserted between twometals desired to be joined, and the assembly is heated and baked tocure the resin whereby articles are obtained wherein the joined surfaceshave not only excellent strength at ordinary temperatures, but alsoretain good strength even though heated at quite elevated temperaturesfor long periods of time. A preferred tape for such use comprises aglass fiber textile impregnated or coated with a mixture of thepolyepoxide, phthalocyanine compound and atomized aluminum powder ordust.

To illustrate the manner in which the invention may be carried out, thefollowing examples are given. It is to be understood, however, that theexamples are for the purpose of illustration and that the invention isnot to be regarded as limited to any of the specific conditions orreactants recited therein. Unless otherwise specified, parts describedin the examples are parts by weight. The polyethers referred to hereinby letter are those described in Us. 2,633,458.

EXAMPLE I This example illustrates the preparation and properties of 4mercaptomethylphenyl 3',4' di(mercaptomethyl) phenyl oxide.

100 parts of sodium hydroxide and 900 parts of ethanol were charged to areaction vessel equipped with stirrer, condenser, dropping funnel,nitrogen and hydrogen sulfide purge. This mixture was cooled andsaturated with hydrogen sulfide. The mixture was then heated to 50 C.and then 100 parts of 4-chloromethylphenyl-3,4'-di- (chloromethyl)phenyl oxide and 100 parts of tetrahydrofuran added slowly over a periodof 3 hours. The mixture was stirred for another 3 hours at 50 C. withhydrogen sulfide purge. With nitrogen purge, ice was then added to thereaction mixture and acetic acid (95 parts) was added until the pH ofthe mixture was 5-6. Water was then added and the mixture extracted with3 portions of chloroform. The extracts combined, dried and solventstripped off. The resulting product was a viscous oil identified as4-mercaptomethylphenyl-3,4-di(mercaptomethyl) phenyl oxide:

CHzSH About 100 parts of Polyether A (polyglycidyl ether of2,2-bis(4hydroxyphenyl) propane), 65 parts of the abovedescribed 4mercaptomethylphenyl 3,4 di(mercaptomethyl) phenyl oxide, and 2 parts of2,4,6-tris(dirnethylaminomethyl)phenol, and parts of solvent made up ofequal volumes of toluene and methyl ethyl ketone were mixed togetherwith stirring. The resulting fluid composition was spread out as acoating (about 2.5 mils thick) on tin panels. The coating was allowed tocure at C. The resulting product was a hard tough solvent resistantcoating. It was cotton free in about minutes, and set hard in mintues.The coating had excellent physical properties and was free of blushing.

EXAMPLE II This example illustrates the preparation and properties of 4mercaptomethylphenyl 3,4' di(mercaptomethyl) phenyl propane.

100 parts of sodium hydroxide and 900 parts of ethanol were charged to areaction vessel equipped with stirrer, condenser, dropping funnel,nitrogen and hydrogen sulfide purge. This mixture was cooled andsaturated with hydrogen sulfide. The mixture was then heated to 50 C.and then 100 parts of 4-chloromethylphenyl-3',4'-di- (chloromethyl)phenyl propane and 100 parts of tetrahydrofuran added over a 3 hourperiod. The mixture was stirred for another 3 hours at 50 C. withhydrogen sulfide purge. With nitrogen purge, ice was then added to thereaction mixture and acetic acid parts) was added until the pH of themixture was 5 6. Water was then added and the mixture extracted with 3portions of 500 ml. of chloroform. The extracts combined, dried andsolvent stripped ofi. The resulting product was a viscous oil identifiedas 4-mercaptomethylphenyl-3',4-di(mercaptomethyl) phenyl propane:

3 (SHaSH EXAMPLE III This example illustrates the preparation andproperties of 4 mercaptomethylphenyl 3',4 di(mercaptomethyl) phenylsulfone.

parts of sodium hydroxide and 900 parts of ethanol were charged to areaction vessel equipped with stirrer, condenser, dropping funnel,nitrogen and hydrogen sulfide purge. This mixture was cooled andsaturated with hydrogen sulfide. The mixture was then heated to 50 C.and then 100 parts of 4-chloromethylphenyl3',4-di(chloromethyl) phenylsulfone and 100 parts of tetrahydrofuran added over 3 hour period. Themixture was stirred for another 3 hours at 5 0 C. with hydrogen sulfidepurge. With nitrogen purge, ice was then added to the reaction mixtureand acetic acid (95 parts) was added until the pH of the mixture was5-6. Water was then added and the mixture extracted with 3 portions ofchloroform. The extracts combined, dried and solvent stripped oil. Theresulting product was identified as 4-rneroaptomethylphenyl-3',4-di(mercaptomethyl) phenyl sulfone.

CHzSH HzSH EXAMPLE IV Toluene is reacted with formaldehyde and HCl toform the trichloromethyl derivative and this is then reacted with NaSHas in the preceding examples. The resulting product,methyl-tri(mercaptomethyl) benzene, is recovered as a light-coloredliquid.

About 100 parts of Polyether A, 40 parts of the abovenotedmethyl-tri(mercaptomethyl) benzene and 2 parts of dibutyl sulfide and 20parts of solvent made up of equal volumes of toluene and methyl ethylketone are mixed together with stirring. The resulting fluid compositionis spread out as a coating and allowed to cure at 25 C. The film driesin a few minutes to form a hard tough coating.

1 1 EXAMPLE v Example IV is repeated with the exception that thepolymercaptan is replaced with each of the following: 1,2,4tri(mercaptoethyl) 3 butyl benzene; 1,2,4 tri-(mercaptomethyl)-3,5-dimethyl benzene; 1,3,5-tri(mercaptomethyl) 4methoxy benzene; l,3,5-tri(mercaptomethyl) 4 hydroxy benzene;3,4,5-tri(mercaptomethyl) furan; 3,4,5-tri(mercaptomethyl) thiophene;and 2,4,6- tri(mercaptomethyl) pyridine. Related results are obtained ineach case.

EXAMPLE VI Examples I to III are repeated with the exception that theaccelerator employed is one of the following: dicyandiamide, pyridine,morpholine, dioctyl sulfide, benzyltrimethylamrnonium chloride andtriphenyl phosphine. Related results are obtained.

EXAMPLE VII We claim as our invention: 1. A member of the groupconsisting of a polymercaptan having the general formula 3 it (RsH)..

o I wherein A is a member of the group consisting of nitrogen or CH, Ris a bivalent alkylene radical containing 1 to 6 carbon atoms, n is aninteger of 3 to 4, and one or tWo ring carbon atoms not attached to theRSH groups are attached to a member of the group consisting of hydrogen,halogen, and alkyl radicals containing up to 4 carbon atoms.

2. 4 mercaptomethylphenyl-3,4-di(mercaptomethyl) phenyl oxide.

References Cited Adams et al. I. Am. Chem. Soc., vol. 81, pp. 4939-40,1959.

HENRY R. JILES, Primary Examiner.

A. L. ROTMAN, Assistant Examiner.

U.S. Cl. X.R.

